Field of the Invention
This invention relates generally to coating systems for building materials, and in particular, to a multi-functional coating system for cementitious composite building materials.
Description of the Related Art
Various coating systems have been developed for protecting the exterior surface of building materials. The coating systems may include sealers, primers, and top coats that are each applied to the building material as separate layers of coating. Each layer of coating serves a different function. For example, sealer is usually applied first to seal any porous surface on the building material and to provide surface reinforcement and water resistance functions. After surface sealing, primer is then applied to the surface followed by top coat. The primer is used as the linkage between the sealer and the top coat to facilitate application of the top coat to the surface as well as to provide other functions. The top coat in turn provides long term weathering durability and decorative functions for the building material. Sealers, primers, and top coats all have different compositions because each is formulated to provide a different set of functions. However, many commercially available sealers and primers are not compatible with fiber cement building materials because of the unique surface chemistry of fiber cement substrates.